A conventional tube coupling device is applied to connect a water supply unit and a water tube together. However, a back pressure produces in the water tube as water stops flowing in the water tube, thus producing bacterium because maintaining the water in the water tube.
A tube coupling device having a check valve is disclosed in U.S. Pat. No. 8,245,721 and includes a coupling member having an upper peripheral casing formed by a peripheral flange and a peripheral wall, a number of openings formed in the peripheral flange and communicative with an environment of the peripheral casing, a water guide plate engaged into the peripheral fence and engaged with the peripheral wall and having one or more passages, a partition member engaged into the peripheral casing and having a bore for water to flow into the coupling member, and a receptacle engaged into the coupling member, a valve member biased by a spring biasing member to engage with the partition member and to form a check valve.
Another tube coupling device having a check valve is disclosed in TW 101216457 and contains a coupling body which includes a large-diameter hole and a small-diameter hole fitting with a resilient element and a check valve, wherein the large-diameter hole has a peripheral groove retained with a stop pad. The coupling body further includes a connector having a guiding plate and connecting with a faucet. The guiding plate has an inlet to guide water to push the check valve, such that the water flows out of the coupling body through a coupling opening. After stopping water supply, the resilient element pushes the check valve upwardly, so that the stop pad is pushed by the check valve to contact the guiding plate, and the small-diameter hole has an orifice communicating with air opening. The peripheral groove of the large-diameter hole has a shoulder defined therein to contact with the guiding plate, such that a plastic gasket fits with the guiding plate, and the small-diameter hole has a fitting sleeve, wherein the stop pad, the gasket, and the fitting sleeve stop water contacting a metal portion of the coupling body.
Another tube coupling device having a check valve is disclosed in TW 102207943 and contains a coupling body and a valve assembly, wherein the valve assembly includes: a check valves with plural wings, a resilient element fitting with the check valve, and a fitting sleeve for accommodating the check valve and the resilient element. The fitting sleeve has plural anti-slip portions, a fourth vertical section, a first lateral section, and a second vertical section perpendicular to a first lateral section, wherein the second vertical section extends to a second lateral section, and a third vertical section extends from a distal end of the second lateral section, a first vertical section extends from the first lateral section, and a diameter defined by the third vertical section is greater than an outer diameter defined by the wings of the check valve. The tube coupling device further contains a valve member which includes a first neck portion for accommodating the check valve and includes a second neck portion, wherein the second neck portion has an inner stop rib and a stepped rim, the first neck portion has a first zone corresponding to the fourth vertical section and the anti-slip portion, and the first zone has at least one recess retaining with the anti-slip portion and has an anti-slip patterns.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages.